21709490833 has 2 divisors, whose sum is σ = 21709490834. Its totient is φ = 21709490832.

The previous prime is 21709490827. The next prime is 21709490843. The reversal of 21709490833 is 33809490712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21592245249 + 117245584 = 146943^2 + 10828^2 .

It is a cyclic number.

It is not a de Polignac number, because 21709490833 - 2²⁹ = 21172619921 is a prime.

It is a super-2 number, since 2×21709490833² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21709490813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10854745416 + 10854745417.

It is an arithmetic number, because the mean of its divisors is an integer number (10854745417).

Almost surely, 2^21709490833 is an apocalyptic number.

It is an amenable number.

21709490833 is a deficient number, since it is larger than the sum of its proper divisors (1).

21709490833 is an equidigital number, since it uses as much as digits as its factorization.

21709490833 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 326592, while the sum is 46.

The spelling of 21709490833 in words is "twenty-one billion, seven hundred nine million, four hundred ninety thousand, eight hundred thirty-three".